Joe Nickell is CSICOP's Senior Research Fellow and author of numerous investigative books. In a recent post to the website of the Committee for Skeptical Inquiry Joe writes:

"Belief in demonic possession is getting a new propaganda boost. Not only has the 1973 horror movie The Exorcist been re-released, but the "true story" that inspired it is chronicled in a reissued book and a made-for-TV movie, both titled Possessed (Allen 2000). However, a year-long investigation by a Maryland writer (Opsasnik 2000), together with my own analysis of events chronicled in the exorcising priest's diary, belie the claim that a teenage boy was possessed by Satan in 1949."